Compositions of dibromomalonamide and their use as biocides

ABSTRACT

A biocidal composition comprising 2,2-dibromomalonamide and an aldehyde-based biocidal compound, and its use for the control of microorganisms in aqueous and water-containing systems.

FIELD OF THE INVENTION

The invention relates to biocidal compositions and methods of their usefor the control of microorganisms in aqueous and water-containingsystems. The compositions comprise 2,2-dibromomalonamide and analdehyde-based biocidal compound.

BACKGROUND OF THE INVENTION

Water systems provide fertile breeding grounds for algae, bacteria,viruses, and fungi some of which can be pathogenic. Microbialcontamination can create a variety of problems, including aestheticunpleasantries such as slimy green water, serious health risks such asfungal, bacterial, or viral infections, and mechanical problemsincluding plugging, corrosion of equipment, and reduction of heattransfer.

Biocides are commonly used to disinfect and control the growth ofmicroorganisms in aqueous and water containing systems. However, not allbiocides are effective against a wide range of microorganisms and/ortemperatures, and some are incompatible with other chemical treatmentadditives. In addition, some biocides do not provide microbial controlover long enough time periods.

While some of these shortcomings can be overcome through use of largeramounts of the biocide, this option creates its own problems, includingincreased cost, increased waste, and increased likelihood that thebiocide will interfere with the desirable properties of the treatedmedium. In addition, even with use of larger amounts of the biocide,many commercial biocidal compounds cannot provide effective control dueto weak activity against certain types of microorganisms or resistanceof the microorganisms to those compounds.

It would be a significant advance in the art to provide biocidecompositions for treatment of water systems that yield one or more ofthe following advantages: increased efficacy at lower concentrations,compatibility with physical conditions and other additives in thetreated medium, effectiveness against a broad spectrum ofmicroorganisms, and/or ability to provide both short term and long termcontrol of microorganisms.

BRIEF SUMMARY OF THE INVENTION

In one aspect, the invention provides a biocidal composition. Thecomposition is useful for controlling microorganisms in aqueous or watercontaining systems. The composition comprises: 2,2-dibromomalonamide andan aldehyde-based biocidal compound selected from the group consistingof glutaraldehyde, tris(hydroxymethyl)nitromethane,4,4-dimethyloxazolidine, 7-ethyl bicyclooxazolidine,1-(3-chloroallyl)-3,5,7-triaza-1-azoniaadamantane chloride, and1,3,5-triethylhexahydro-s-triazine.

In a second aspect, the invention provides a method for controllingmicroorganisms in aqueous or water containing systems. The methodcomprises treating the system with an effective amount of a biocidalcomposition as described herein.

DETAILED DESCRIPTION OF THE INVENTION

As noted above, the invention provides a biocidal composition andmethods of using it in the control of microorganisms. The compositioncomprises: 2,2-dibromomalonamide and an aldehyde-based (i.e.,aldehyde-containing or aldehyde-releasing) biocidal compound selectedfrom the group consisting of glutaraldehyde,tris(hydroxymethyl)nitromethane, 4,4-dimethyloxazolidine, 7-ethylbicyclooxazolidine, 1-(3-chloroallyl)-3,5,7-triaza-1-azoniaadamantanechloride, and 1,3,5-triethylhexahydro-s-triazine. It has surprisinglybeen discovered that combinations of 2,2-dibromomalonamide and analdehyde-based biocidal compound as described herein, at certain weightratios, are synergistic when used for microorganism control in aqueousor water containing media. That is, the combined materials result inimproved biocidal properties than would otherwise be expected based ontheir individual performance. The synergy permits reduced amounts of thematerials to be used to achieve the desired biocidal performance, thusreducing problems caused by growth of microorganisms in industrialprocess waters while potentially reducing environmental impact andmaterials cost.

For the purposes of this specification, the meaning of “microorganism”includes, but is not limited to, bacteria, fungi, algae, and viruses.The words “control” and “controlling” should be broadly construed toinclude within their meaning, and without being limited thereto,inhibiting the growth or propagation of microorganisms, killingmicroorganisms, disinfection, and/or preservation. In some preferredembodiments, “control” and “controlling” mean inhibiting the growth orpropagation of microorganisms. In further embodiments, “control” and“controlling” mean the killing of microorganisms.

The term “2,2-dibromomalonamide” refers to a compound represented by thefollowing chemical formula:

2,2-Dibromomalonamide and the aldehyde-based biocidal compounds of theinvention are commercially available and/or can be readily prepared bythose skilled in the art using well known techniques. The1-(3-chloroallyl)-3,5,7-triaza-1-azoniaadamantane chloride compound maybe the cis isomer, the trans isomer, or a mixture of cis and transisomers. Preferably, it is the cis isomer or a mixture of the cis andtrans isomers.

In some embodiments of the invention, the weight ratio of2,2-dibromomalonamide to the aldehyde-based biocidal compound is betweenabout 100:1 and about 1:1500.

In some embodiments of the invention, the weight ratio of2,2-dibromomalonamide to the aldehyde-based biocidal compound is betweenabout 100:1 and about 1:400.

In some embodiments, the weight ratio of 2,2-dibromomalonamide to thealdehyde-based biocidal compound is between about 50:1 and about 1:350.

In some embodiments, the weight ratio of 2,2-dibromomalonamide to thealdehyde-based biocidal compound is between about 9:1 and about 1:320.

In some embodiments, the aldehyde-based biocidal compound isglutaraldehyde and the weight ratio of 2,2-dibromomalonamide toglutaraldehyde is from about 20:1 to about 1:20, alternatively fromabout 9:1 to about 1:9, or alternatively from about 9:1 to about 1:1. Insome embodiments the weight ratio is from about 2:1 to about 1:350,alternatively from about 1:1 to about 1:330, or alternatively from about1:5 to about 1:320. In some embodiments, the weight ratio is from about20:1 to about 1:400, alternatively from about 10:1 to about 1:350, oralternatively from about 9:1 to about 1:320.

In some embodiments, the aldehyde-based biocidal compound istris(hydroxymethyl)nitromethane and the weight ratio of2,2-dibromomalonamide to tris(hydroxymethyl)nitromethane is from about1:1 to about 1:50, alternatively from about 1:2 to about 1:40, oralternatively from about 1:2.5 to about 1:40.

In some embodiments, the aldehyde-based biocidal compound is 7-ethylbicyclooxazolidine and the weight ratio of 2,2-dibromomalonamide to7-ethyl bicyclooxazolidine is from about 5:1 to about 1:1500,alternatively from about 1:1 to about 1:1300, or alternatively fromabout 1:1 to about 1:1280, or alternatively from about 1:1.2 to about1:1280.

In some embodiments, the aldehyde-based biocidal compound is1-(3-chloroallyl)-3,5,7-triaza-1-azoniaadamantane chloride and theweight ratio of 2,2-dibromomalonamide to1-(3-chloroallyl)-3,5,7-triaza-1-azoniaadamantane chloride is from about10:1 to about 1:350, alternatively from about 4:1 to about 1:320, oralternatively from about 3.2:1 to about 1:320.

In some embodiments, the aldehyde-based biocidal compound is4,4-dimethyloxazolidine and the weight ratio of 2,2-dibromomalonamide to4,4-dimethyloxazolidine is from about 5:1 to about 1:5, alternativelyfrom about 1:2 to about 1:3, or alternatively about 1:2.5.

In some embodiments, the aldehyde-based biocidal compound is1,3,5-triethylhexahydro-s-triazine and the weight ratio of2,2-dibromomalonamide to 1,3,5-triethylhexahydro-s-triazine is fromabout 10:1 to about 1:30, alternatively from about 4:1 to about 1:20, oralternatively from about 2:1 to about 1:16.

The composition of the invention is useful for controllingmicroorganisms in a variety of aqueous and water containing systems.Examples of such systems include, but are not limited to, paints andcoatings, aqueous emulsions, latexes, adhesives, inks, pigmentdispersions, household and industrial cleaners, detergents, dishdetergents, mineral slurries polymer emulsions, caulks and adhesives,tape joint compounds, disinfectants, sanitizers, metalworking fluids,construction products, personal care products, textile fluids such asspin finishes, industrial process water (e.g. oilfield water, pulp andpaper water, cooling water), oilfield functional fluids such as drillingmuds and fracturing fluids, fuels, air washers, wastewater, ballastwater, filtration systems, and swimming pool and spa water. Preferredaqueous systems are metal working fluids, personal care, household andindustrial cleaners, industrial process water, and paints and coatings.Particularly preferred are industrial process water, paints andcoatings, metal working fluids, and textile fluids such as spinfinishes.

A person of ordinary skill in the art can readily determine, withoutundue experimentation, the effective amount of the composition thatshould be used in any particular application to provide microorganismcontrol. By way of illustration, a suitable actives concentration (totalfor both 2,2-dibromomalonamide and aldehyde-based biocidal compound) istypically at least about 1 ppm, alternatively at least about 3 ppm,alternatively at least about 7 ppm, alternatively at least about 10 ppm,or alternatively at least about 100 ppm based on the total weight of theaqueous or water containing system. In some embodiments, a suitableupper limit for the actives concentration is about 1000 ppm,alternatively about 500 ppm, alternatively about 100 ppm, alternativelyabout 50 ppm, alternatively about 30 ppm, alternatively about 15 ppm,alternatively about 10 ppm, or alternatively about 7 ppm, based on thetotal weight of the aqueous or water containing system.

The components of the composition can be added to the aqueous or watercontaining system separately, or pre-blended prior to addition. A personof ordinary skill in the art can easily determine the appropriate methodof addition. The composition can be used in the system with otheradditives such as, but not limited to, surfactants, ionic/nonionicpolymers and scale and corrosion inhibitors, oxygen scavengers, and/oradditional biocides.

The following examples are illustrative of the invention but are notintended to limit its scope. Unless otherwise indicated, the ratios,percentages, parts, and the like used herein are by weight.

EXAMPLES

The results provided in the Examples are generated using a growthinhibition assay or a kill assay. Details of each assay are providedbelow.

Kill Assay. This assay is used as a preliminary evaluation of synergybetween the actives. The procedure is as follows. A mineral saltssolution (0.2203 g of CaCl₂, 0.1847 g of MgSO₄, and 0.2033 g of NaHCO₃in 1 L water, approximately pH 8) is inoculated with equal amounts(about 10⁷ CFU/ml) of a mixture of Pseudomonas aeruginosa ATCC 10145 andStaphylococcus aureus ATCC 6538. Aliquots of the cell suspension arethen treated with 2,2-dibromomalonamide (“DBMAL”), an aldehyde-basedbiocidal compound, and their combinations at various concentrationlevels. After incubating at 37° C. for 2 hours, the biocidal efficacy isdetermined on the basis of the minimum biocide concentration (MBC)needed to completely kill the bacterial cells in the aliquots. The MBCvalues are then used to calculate a synergy index (SI) values.

Summaries of the kill assay results are presented in the individualExamples. In each table, MBC values for each biocide and the blendstested are presented. Likewise, the Synergy Index (“SI”) values for thecombinations are listed. SI is calculated with the following equation:Synergy Index=C _(a) /C _(A) +M _(b) /C _(B)

where

-   -   C_(a): Concentration of biocide A required for complete        bacterial kill when used in combination with biocide B    -   C_(A): Concentration of biocide A required for complete        bacterial kill when used alone    -   C_(b): Concentration of biocide B required for complete        bacterial kill when used in combination with biocide A    -   C_(B): Concentration of biocide B required for complete        bacterial kill when used alone        The SI values are interpreted as follows:    -   SI<1: Synergistic    -   SI=1: Additive    -   SI>1: Antagonistic

Growth Inhibition Assay. The growth inhibition assay used in theExamples measures inhibition of growth (or lack thereof) of a microbialconsortium Inhibition of growth can be the result of killing of thecells (so no growth occurs), killing of a significant portion of thepopulations of cells so that regrowth requires a prolonged time, orinhibition of growth without killing (stasis). Regardless of themechanism of action, the impact of a biocide (or combination ofbiocides) can be measured over time on the basis of an increase in thesize of the community.

The assay measures the efficacy of one or more biocides at preventinggrowth of a consortium of bacteria in a dilute mineral salts medium. Themedium contains (in mg/l) the following components: FeCl₃.6H₂O (1);CaCl₂.2H₂O (10); MgSO₄.7H₂O (22.5); (NH₄)₂SO₄ (40); KH₂PO₄ (10); K₂HPO₄(25.5); Yeast Extract (10); and glucose (100). After all components areadded to deionized water, the pH of the medium is adjusted to 7.5.Following filter sterilization, aliquots are dispensed in 100 ulquantities to sterile microtiter plate wells. Dilutions of DBMAL and/or“Biocide B” are then added to the microtiter plate. After preparing thecombinations of actives as illustrated below, each well is inoculatedwith 100 μl of a cell suspension containing ca. 1×10⁶ cells permilliliter of a mixture of Pseudomonas aeruginosa, Klebsiellapneumoniae, Staphylococcus aureus, and Bacillus subtilis. The finaltotal volume of medium in each well is 300 μl. Once prepared asdescribed herein, the concentration of each active ranges from 25 ppm to0.19 ppm as illustrated in Table 1. The resulting matrix allows testingof eight concentrations of each active and 64 combinations of actives inthe ratios (of actives).

TABLE 1 Template for microtiter plate-based synergy assay showingconcentrations of each active. Ratios are based on weight (ppm) of eachactive. Biocide B (mg/l) 25.000 12.500 6.250 3.13 1.56 0.78 0.39 0.19DBMAL (mg/l) 25.000 1:1 1:2 1:4 1:8  1:16  1:32  1:64  1:128 12.500 2:11 1:2 1:4 1:8  1:16  1:32  1:64 6.250 4:1 2:1 1 1:2 1:4 1:8  1:16  1:323.13 8:1 4:1 2:1 1 1:2 1:4 1:8  1:16 1.56 16:1  8:1 4:1 2:1 1 1:2 1:41:8 0.78 32:1  16:1  8:1 4:1 2:1 1 1:2 1:4 0.39 64:1  32:1  16:1  8:14:1 2:1 1 1:2 0.19 128:1  64:1  32:1  16:1  8:1 4:1 2:1 1:1Controls (not shown) contain the medium with no biocide added. Afterpreparing the combinations of actives as illustrated above, each well isinoculated with 100 μA of a cell suspension containing ca. 1×10⁶ cellsper milliliter of a mixture of Pseudomonas aeruginosa, Klebsiellapneumoniae, Staphylococcus aureus, and Bacillus subtilis. The finaltotal volume of medium in each well is 300 μl.

Immediately after the microtiter plates are prepared, the opticaldensity (OD) readings for each well is measured at 580 nm and the platesare then incubated at 37° C. for 24 hr. After the incubation period, theplates are gently agitated before OD₅₈₀ values are collected. The OD₅₈₀values at T₀ are subtracted from T₂₄ values to determine the totalamount of growth (or lack thereof) that occurs. These values are used tocalculate the percent inhibition of growth caused by the presence ofeach biocide and each of the 64 combinations. A 90% inhibition of growthis used as a threshold for calculating synergy index (SI) values withthe following equation:Synergy Index=M _(DBMAL) /C _(DBMAL) +M _(B) /C _(B)

where

-   -   C_(DBMAL): Concentration of DBMAL required to inhibit ˜90% of        bacterial growth when used alone    -   C_(B): Concentration of biocide (B) required to inhibit ˜90% of        bacterial growth when used alone.    -   M_(DBMAL): Concentration of DBMAL required to inhibit ˜90% of        bacterial growth when used in combination with biocide (B).    -   M_(B): Concentration of biocide (B) required to inhibit ˜90% of        bacterial growth when used in combination with DBMAL        The SI values are interpreted as follows:    -   SI<1: Synergistic combination    -   SI=1: Additive combination    -   SI>1: Antagonistic combination

In the Examples below, the amounts of biocides in the solution aremeasured in mg per liter of solution (mg/l). Since solution densitiesare approximately 1.00, the mg/l measurement corresponds to weight ppm.Both units may therefore be used interchangeably in the Examples.

Example 1 DBMAL and Glutaraldehyde

Kill Assay Results. The kill assay result on combinations of DBMAL andglutaraldehyde (Glut) are presented in Table 2. In this assay, whentested alone, the concentrations of DBMAL and glutaraldehyde needed toachieve complete kill of the test strains is 66.7 mg/l and 29.6 mg/l,respectively. However, when tested together in a 1:1 blend, only 14.8mg/l of each active is required; the corresponding SI is 0.72. Othercombinations of DBMAL and glut exhibit synergy.

TABLE 2 MBC of DBMAL, Glut, and combinations thereof 1st 2nd Activebiocide biocide weight DBMAL Glut ratio Concn. Concn. Synergy (1st:2nd)(mg/l) (mg/l) Index DBMAL 66.7 0.0 alone 9:1 40.0 4.4 0.75 3:1 14.8 4.90.57 1:1 14.8 14.8 0.72 1:3 7.4 22.2 0.86 1:9 3.0 26.7 0.95 Glut 0.029.6 alone

Growth Inhibition Assay Results. Table 3 shows the assay results forDBMAL, glutaraldehyde, and combinations. The concentration ofglutaraldehyde needed to provide at least 90% inhibition of growth ofthe microorganism consortium is 125 mg/l and that for DBMAL is 12.5mg/l.

TABLE 3 Percent inhibition of growth in a species-defined microbialconsortium by glutaraldehyde (glut) and DBMAL alone and combinations ofthese actives after a 24-hour incubation period. Numbers representpercent inhibition of growth as measured by optical density measurements(580 nm) at time = 24 hours compared with time = 0 values. % SingleActives (mg/l) Inhibition % of growth Inhibition % Combinations of DBMALand Glut in DBMAL of growth Glut Inhibition DBMAL Untreated Concn. byConcn. of growth Concn. Glut Concn. (mg/l) Control (mg/l) DBMAL (mg/l)by Glut. (mg/l) 500.0 250.0 125.0 62.5 31.25 15.63 7.81 3.91 22 25.0 105500.0 100 25.0 97 98 93 100 99 100 100 100 14 12.5 107 250.0 100 12.5 98100 100 100 100 100 100 100 0 6.25 50 125.0 100 6.25 100 100 93 100 10050 23 16 0 3.13 38 62.5 0 3.13 64 100 100 100 91 43 6 0 0 1.56 11 31.2521 1.56 99 100 100 100 27 26 5 0 8 0.78 34 15.63 20 0.78 99 99 97 100 7418 2 0 0 0.39 0 7.81 18 0.39 97 100 100 100 68 13 0 0 22 0.19 0 3.91 00.19 95 100 100 100 70 12 0 0Table 4 shows ratios of DBMAL and glutaraldehyde found to be synergisticunder the growth inhibition assay.

TABLE 4 DBMAL Glut Ratio Synergy Concn. Concn. (DBMAL Index (mg/l)(mg/l) to Glut) (SI) 6.25 31.25 1:5  0.75 3.13 62.5 1:20 0.75 3.13 31.251:10 0.50 1.56 62.5 1:40 0.63 1.56 31.25 1:20 0.37 0.78 62.5 1:80 0.560.39 62.5  1:160 0.53 0.19 62.5  1:320 0.52

Example 2 DBMAL and CTAC

Inhibition Growth Assay Results. Table 5 shows the inhibition growthassay results for DBMAL,1-(3-chloroallyl)-3,5,7-triaza-1-azoniaadamantane chloride (“CTAC”), andcombinations.

TABLE 6 Percent inhibition of growth in a species-defined microbialconsortium by CTAC and DBMAL alone and combinations of these activesafter a 24-hour incubation period. Numbers represent percent inhibitionof growth as measured by optical density measurements (580 nm) at time =24 hours compared with time = 0 values. % Single Actives (mg/l)Inhibition % of growth Inhibition % Combinations of DBMAL and CTAC inDBMAL of growth CTAC Inhibition DBMAL Untreated Concn. by Concn. ofgrowth Concn. CTAC Concn. (mg/l) Control (mg/l) DBMAL (mg/l) by CTAC(mg/l) 250.0 125.0 62.5 31.25 15.625 7.8125 3.91 1.95 20 25 100 250.0 9825.0 100 99 97 99 99 100 99 99 5 12.5 97 125.0 100 12.5 100 100 100 99100 100 99 100 0 6.25 44 62.5 41 6.25 100 100 100 100 100 100 100 100 03.13 50 31.25 35 3.13 100 100 100 100 100 86 40 22 12 1.56 34 15.625 01.56 99 99 100 100 31 18 6 0 20 0.78 18 7.81 9 0.78 100 100 99 89 3 3 00 3 0.39 0 3.91 0 0.39 100 100 99 39 0 0 0 0 0 0.19 0 1.95 0 0.19 99 10098 0 0 0 0 0Table 7 shows ratios of DBMAL and CTAC found to be synergistic under thegrowth inhibition assay. Ratios are based on concentrations of theactives.

TABLE 7 DBMAL CTAC Ratio Synergy Concn. Concn. (DBMAL: Index (mg/l)(mg/l) CTAC) (SI) 6.25 31.25 1:5  0.75 6.25 15.63  1:2.5 0.63 6.25 7.81 1:1.25 0.56 6.25 3.91 1.6:1   0.53 6.25 1.95 3.2:1   0.52 3.13 62.501:20 0.75 3.13 31.25 1:10 0.50 3.13 15.63 1:5  0.38 1.56 62.50 1:40 0.621.56 31.25 1:20 0.37 0.78 62.50 1:80 0.56 0.39 62.50  1:160 0.53 0.1962.50  1:320 0.52

Example 3 DBMAL and TN

Inhibition Growth Assay Results. Table 8 shows the inhibition growthassay results for DBMAL, tris(hydroxymethyl)nitromethane (“TN”), andcombinations thereof.

TABLE 8 Percent inhibition of growth in a species-defined microbialconsortium by TN and DBMAL alone and combinations of these actives aftera 24-hour incubation period. Numbers represent percent inhibition ofgrowth as measured by optical density measurements (580 nm) at time = 24hours compared with time = 0 values. % Single Actives (mg/l) Inhibition% of growth Inhibition % Combinations of DBMAL and TN in DBMAL of growthTN Inhibition DBMAL Untreated Concn. by concn. of growth concn. TNconcn. (mg/l) Control (mg/l) DBMAL (mg/l) by TN (mg/l) 1000.0 500.0250.0 125.0 62.5 31.25 15.63 7.81 0 25.0 100 1000.0 100 25.0 100 100 100100 100 100 100 100 2 12.5 100 500.0 100 12.5 100 100 100 100 100 100100 100 2 6.25 0 250.0 100 6.25 100 100 100 100 100 100 100 0 2 3.13 0125.0 100 3.13 100 100 100 100 100 100 0 0 5 1.56 0 62.5 50 1.56 100 100100 100 100 0 0 0 2 0.78 0 31.25 0 0.78 100 100 100 100 76 0 0 0 0 0.392 15.63 4 0.39 100 100 100 100 0 0 0 0 0 0.19 0 7.81 0 0.19 100 100 100100 0 0 0 0Table 9 shows concentrations of concentrations of DBMAL and TN found tobe synergistic. The ratios are based on concentrations (in mg/l) of thetwo actives.

TABLE 9 DBMAL TN Ratio Synergy concn. concn. (DBMAL Index (mg/l) (mg/l)to TN) (SI) 6.25 31.25 1:5  0.75 6.25 15.63  1:2.5 0.63 3.13 62.5 1:200.75 3.13 31.25 1:10 0.5 1.56 62.5 1:40 0.63

Example 4 DBMAL and EBO

Inhibition Growth Assay Results. Table 10 shows the inhibition growthassay results for DBMAL, 7-ethyl bicyclooxazolidine (“EBO”), andcombinations thereof.

TABLE 10 Percent inhibition of growth in a species-defined microbialconsortium by 7-ethyl bicyclooxazolidine (“EBO”)and DBMAL alone andcombinations of these actives after a 24-hour incubation period. Numbersrepresent percent inhibition of growth as measured by optical densitymeasurements (580 nm) at time = 24 hours compared with time = 0 values.% Single Actives (mg/l) Inhibition % of growth Inhibition % Combinationsof DBMAL and EBO in DBMAL of growth EBO Inhibition DBMAL Untreatedconcn. by concn. of growth concn. EBO concn. (mg/l) Control (mg/l) DBMALmg/l by EBO (mg/l) 1000.0 500.0 250.0 125.0 62.5 31.25 15.63 7.81 8 25.0100 1000.0 100 25 98 99 98 100 100 99 100 99 10 12.5 99 500.0 96 12.5 9999 97 100 87 99 91 99 5 6.25 52 250.0 71 6.25 100 99 97 99 99 94 98 95 03.13 0 125.0 10 3.13 98 83 97 93 0 0 0 0 0 1.56 0 62.5 3 1.56 98 98 9931 0 0 0 0 0 0.78 0 31.25 0 0.78 98 99 97 0 0 0 0 0 6 0.39 0 15.63 00.39 96 99 98 0 0 0 0 0 2 0.19 7 7.81 0 0.19 90 100 97 0 0 0 0 0Table 11 shows concentrations of Concentrations of DBMAL and EBO foundto be synergistic. The ratios are based on concentrations (in mg/l) ofthe two actives.

TABLE 11 DBMAL EBO Ratio Synergy concn. concn. (DBMAL Index (mg/l)(mg/l) to EBO) (SI) 6.25 125 1:20 0.75 6.25 62.5 1:10 0.63 6.25 31.251:5  0.56 6.25 15.63  1:2.5 0.53 6.25 7.81  1:1.2 0.52 3.13 250 1:800.75 1.56 125 1:80 0.38 0.78 250  1:320 0.56 0.39 250  1:640 0.54 0.19250  1:1280 0.52

Example 5 DBMAL and 4,4-Dimethyloxazolidine

Growth Inhibition Assay Results. Table 12 shows the inhibition growthassay results for DBMAL, 4,4-Dimethyloxazolidine (“4,4-D”), andcombinations thereof.

TABLE 12 Percent inhibition of growth in a species-defined microbialconsortium by 4,4-Dimethyloxazolidine (“4,4-D”) and DBMAL alone andcombinations of these actives after a 24-hour incubation period. Numbersrepresent percent inhibition of growth as measured by optical densitymeasurements (580 nm) at time = 24 hours compared with time = 0 values.% Single Actives (mg/l) Inhibition % of growth Inhibition % Combinationsof DBMAL and 4,4-D in DBMAL of growth 4,4-D Inhibition DBMAL UntreatedConcn. by Concn. of growth Concn. 4,4-D Concn. (mg/l) Control (mg/l)DBMAL (mg/l) by 4,4-D (mg/l) 1000.0 500.0 250.0 125.0 62.5 31.25 15.637.81 2 25.0 100 1000.0 100 25.0 99 100 99 100 100 100 100 100 1 12.5 100500.0 100 12.5 100 100 100 100 100 100 100 100 0 6.25 0 250.0 99 6.25100 100 100 100 100 100 100 0 0 3.13 0 125.0 100 3.13 100 100 100 100100 51 0 0 5 1.56 2 62.5 98 1.56 100 100 100 100 100 0 0 0 0 0.78 031.25 13 0.78 100 100 2 100 100 0 0 0 1 0.39 6 15.63 2 0.39 100 100 100100 85 0 0 0 0 0.19 0 7.81 0 0.19 100 100 0 100 100 0 0 0Table 13 shows concentrations of Concentrations of DBMAL and4,4-Dimethyloxazolidine (“4,4-D”) found to be synergistic. The ratiosare based on concentrations (in mg/l) of the two actives.

TABLE 13 DBMAL 4,4-D Ratio Synergy Concn. Concn. (DBMAL Index (mg/l)(mg/l) to 4,4-D) (SI) 6.25 15.63 1:2.5 0.75

Example 6 DBMAL and 1,3,5-Triethylhexahydro-s-triazine

Growth Inhibition Assay Results. Table 12 shows the inhibition growthassay results for DBMAL, 1,3,5-Triethylhexahydro-s-triazine (“TEHT”),and combinations thereof.

TABLE 12 Percent inhibition of growth in a species-defined microbialconsortium by 1,3,5-Triethylhexahydro-s-triazine (“TEHT”) and DBMALalone and combinations of these actives after a 24-hour incubationperiod. Numbers represent percent inhibition of growth as measured byoptical density measurements (580 nm) at time = 24 hours compared withtime = 0 values. % Single Actives (mg/l) Inhibition % of growthInhibition % Combinations of DBMAL and TEHT in DBMAL of growth TEHTInhibition DBMAL Untreated Concn. by Concn. of growth Concn. TEHT concn.(mg/l) Control (mg/l) DBMAL (mg/l) by TEHT (mg/l) 25 12.5 6.25 3.13 1.560.78 0.39 0.19 1 25.0 96 25.0 100 25.0 100 100 100 100 100 100 100 100 012.5 97 12.5 98 12.5 100 100 100 99 100 99 99 99 0 6.25 32 6.25 82 6.25100 100 100 100 50 12 5 12 0 3.13 45 3.13 49 3.13 100 100 100 75 0 0 0 02 1.56 32 1.56 22 1.56 100 100 92 18 0 13 8 0 0 0.78 30 0.78 10 0.78 100100 100 20 0 9 0 0 0 0.39 8 0.39 11 0.39 99 91 100 0 0 0 0 0 3 0.19 130.19 10 0.19 100 91 56 0 0 0 0 0Table 13 shows concentrations of Concentrations of DBMAL and1,3,5-Triethylhexahydro-s-triazine (“TEHT”) found to be synergistic. Theratios are based on concentrations (in mg/l) of the two actives.

TABLE 13 DBMAL TEHT concn. concn. (mg/l) (mg/l) SI Ratio 3.13 6.25 0.751:2 1.56 6.25 0.63 1:4 0.78 6.25 0.56 1:8 0.39 6.25 0.53  1:16 6.2503.13 0.75 2:1

While the invention has been described above according to its preferredembodiments, it can be modified within the spirit and scope of thisdisclosure. This application is therefore intended to cover anyvariations, uses, or adaptations of the invention using the generalprinciples disclosed herein. Further, the application is intended tocover such departures from the present disclosure as come within theknown or customary practice in the art to which this invention pertainsand which fall within the limits of the following claims.

What is claimed is:
 1. A biocidal composition for controllingmicroorganisms in an aqueous or water-containing system, the compositioncomprising: 2,2-dibromomalonamide and an aldehyde-based biocidalcompound; wherein the aldehyde-based biocidal compound istris(hydroxymethyl)nitromethane and the weight ratio of2,2-dibromomalonamide to tris(hydroxymethyl)nitromethane is from about1:2 to about 1:40.
 2. A composition according to claim 1 which is:paint, coating, aqueous emulsion, latex, adhesive, ink, pigmentdispersion, household or industrial cleaner, detergent, dish detergent,mineral slurry polymer emulsion, caulk, adhesive, tape joint compound,disinfectant, sanitizer, metalworking fluid, construction product,personal care product, textile fluid, spin finish, industrial processwater, oilfield functional fluid, fuel, air washer, wastewater, ballastwater, filtration systems, or swimming pool and spa water.
 3. A methodfor controlling microorganism growth in an aqueous or water-containingsystem, the method comprising treating the aqueous or water-containingsystem with an effective amount of a composition according to claim 1.4. A method according to claim 3 wherein the aqueous or water-containingsystem is paint, coating, aqueous emulsion, latex, adhesive, ink,pigment dispersion, household or industrial cleaner, detergent, dishdetergent, mineral slurry polymer emulsion, caulk, adhesive, tape jointcompound, disinfectant, sanitizer, metalworking fluid, constructionproduct, personal care product, textile fluid, spin finish, industrialprocess water, oilfield functional fluid, fuel, air washer, wastewater,ballast water, filtration system, or swimming pool and spa water.
 5. Amethod according to claim 3 wherein the composition inhibits the growthof microorganisms in the aqueous or water-containing system.
 6. A methodaccording to claim 3 wherein the composition kills microorganisms in theaqueous or water-containing system.